Thanks Cal,
I don't know much about the 289 thin wall. I will have to do
some research to see what I can find out about it.
Here is a exerpt from "GT40 The Early years" By Richard Guest......
These developments included wider rear bodywork to accommodate wider racing tyres, with six spoke magnesium knock on wheels, more efficient Girling brakes, a very strong engine:- 400 BHP at 6,500 rpm and 385 lbs.ft of torque in 1968. In 1969 this was raised to 425 BHP at slightly lower revs of 6,250 and 396 lbs of torque at 4,750 rpm with a 302 ci. engine plus other improvements
Hersh
